The focus of this conference is on the mechanisms of intracellular protein degradation with an emphasis on the ubiquitin-dependent proteolytic pathway and other . Ubiquitin is a small, highly conserved eukaryotic protein. It functions in protein breakdown by becoming covalently linked to other proteins and serves as a reusable recognition signal for proteolysis. The ubiquitin system appears responsible for controlling the levels of many key developmental regulators including: cyclins, MATalpha2 repressor, phytochrome, and a variety of oncogene products including p53. The ubiquitin pathway or elements thereof are also involved in a number of important cellular processes including the modification of chromatin. structure, stress response, cell/cell interactions, signal transduction, DNA repair, cell cycle, sex determination, cytoskeletal organization, ribosome biogenesis, viral assembly, antigen presentation, and various neuronal disorders (including Alzheimer's), but its role(s) are unclear. The details and breadth of the ubiquitin system are emerging at an ever increasing rate making this type of meeting vital. At the same time, it has become clear that the ubiquitin-dependent proteolytic system is not the only one that exists in cells. In particular, prokaryotes and organelles use other types of ATP-dependent proteolytic pathways. Discussion of these non-ubiquitin systems in prokaryotes and eukaryotes is also planned. Specific sessions will include the biochemistry, molecular biology and genetics of the ubiquitin system, targets and functions of the ubiquitin pathway, non-ubiquitin proteolytic systems in eukaryotes, recognition signals for protein breakdown, the proteasome, proteolysis and antigen presentation, enzymology and regulation of protein breakdown in prokaryotes, and protein degradation in organelles.